1. Field of the Invention
The present invention relates to a car power supply system comprising a plurality of generators.
2. Description of the Prior Art
FIG. 7 is a sectional view of a car AC generator of the prior art. This AC generator comprises a case 3 formed by connecting an aluminum front bracket 1 and an aluminum rear bracket 2 by a bolt 3B, a generator shaft 5 provided in the case 3 and fitted with a pulley 4 for receiving the torque of an engine transmitted from a belt at one end, a randol type rotor 6 fixed to the generator shaft 5, fans 6F fixed to both side of the rotor 6, a stator 7A fixed on the inner wall of the case 3, slip rings 8, fixed to the other end of the generator shaft 5, for supplying a current to the rotor 6, a pair of brushes 9 and 9 which slide in contact with the slip rings 8, a brush holder 10 for storing the brushes 9 and 9, a rectifier 11, electrically connected to the stator 7A, for rectifying an AC generated in the stator 7A into a DC, a heat sink 12 attached to the brush holder 10, and a regulator 13, attached to the heat sink 12, for regulating an AC voltage generated in the stator 7A. Denoted by 14a and 14b are bearings, and 15 brackets for connecting the AC generator to the engine.
The above rotor 6 comprises a rotor coil 6A for generating a magnetic flux with a current supplied and a pole core 6B for covering the rotor coil 6A and forming a magnetic pole with the magnetic flux. The pole core 6B consists of a pair of pole core unit 6x and a pole core unit 6y which engage with each other. The pole core units 6x and 6y are made from iron and have claw-like magnetic poles 62 and 62, respectively.
The stator 7A comprises a stator core 17A and a stator coil 17B formed of a conductor wound round the stator core 17A. An AC is generated in the stator coil 17B by the rotation of the rotor 6 according to changes in the magnetic flux from the rotor coil 6A.
In the car AC generator constituted above, a current is supplied to the rotor coil 6A from a battery (unshown) through the brushes 9 and 9 and the slip rings 8 to generate a magnetic flux. Meanwhile, the pulley 4 is driven by the engine and the rotor 6 is turned by the generator shaft 5, thereby giving a rotating field to the stator coil 17B to generate electromotive force in the stator coil 17B. This AC electromotive force is rectified into a DC by the diodes 16 and 16 of the rectifier 11, the DC is regulated by the regulator 13, and the regulated DC is charged into the battery and supplied to electric loads.
FIG. 8 is a sectional view of a car brushless AC generator of the prior art. The same or corresponding elements as those of FIG. 7 are given the same reference symbols and their descriptions are omitted. In the case of this car brushless AC generator, when the engine is started, an excitation current is supplied from the battery to an excitation coil incorporated in an excitation core 19 and the pole core units 6x and 6y of the rotor 6 are turned by the rotation of the generator shaft 5, whereby electromotive force is generated in the stator coil 17B of the stator 7A. This AC electromotive force is rectified into a DC by the diodes 16 and 16 of the rectifier 11, the DC is regulated by the regulator 13A, and the regulated DC is charged into the battery and supplied to electric loads.
FIG. 9 is a diagram showing a car power supply system of the prior art comprising the generator shown in FIG. 7 and FIG. 8.
The generator 20 for supplying power to the electric loads of a vehicle is connected to an engine E by the above brackets 15 and attachment arms 15A. A belt 20b is stretched between the pulley 20a of the generator 20 and the pulley Fa of the crank shaft F of the engine E.
When the engine E is started, an excitation current is supplied to the rotor coil 6A of the generator 20 and the generator shaft 5 is turned by the belt 20b for transmitting the torque of the engine E to start the power generation of the generator 20.